The present invention relates in general to apparatuses for sharpening razor blades, and relates more particularly to a motor operated apparatus for sharpening razor blades used for shaving hair from the human body.
Hand-held safety razors, typically used for shaving the face, legs, and other hairy regions of the human body, generally consists of a metal and/or plastic handle attached to a razor head for holding one to three razor blades, with multiple blades being arranged in parallel. Generally, the razor blades are capable of a maximum number of close shaves between four and 15, depending on the coarseness of the hair being shaved. Thereafter, the cutting edge portion of the blade become so dull that the user must either change blades or, in the case of disposable razors, must discard the dull razor for a new one.
The inventor of the present device was previously granted U.S. Pat. No. 5,036,731 on a hand operated device for sharpening the blades of such hand-held razors. Although this hand operated device also greatly extended the useful life of such razors, the hand operation thereof was somewhat slow and required precise hand positioning of the razor handle for each sharpening stroke in order to achieve maximum effectiveness. There is therefore a need for a quick, precise and automated means for re-sharpening the blades of hand-held razors in order to extend their useful life.
It is accordingly one object of the present invention to provide a motorized apparatus for sharpening the cutting edge of one or more razor blades in the head of a hand-held razor. Other objects of this invention are to provide an apparatus which can rapidly and automatically sharpen one or more blades while precisely positioning the head in which the blades are mounted. It is also desirable to provide such an apparatus in a compact and durable form.
In accordance with the present invention, there is provided an improved electrically operated razor blade sharpening apparatus (sharpener) for sharpening the cutting edge of one or more razor blades that are mounted within a razor head having a plastic or metal handle attached thereto. The sharpener may have a plastic or metal housing which may contain all of the moving components. An electric drive system of the sharpener comprises a small electric motor and a reduction gear assembly which drives a cam assembly arranged to slidingly oscillate back and forth a carriage on which is mounted a rectangular strip or slide of mildly abrasive material, which may be a hard vitreous material such as, for example, glass, porcelain, or a ceramic.
The abrasive slide is just wide enough to fit between the outer lips of a typical razor blade head so that the head lips will engage opposite edges of the slide to provide a track for the blade(s) to follow during the oscillatory motion of the slide carriage. The electric motor is operated by an electrical system, which includes a switch that is mounted on the outside of the housing and is manually operated to actuate the electric motor. The electric system also includes a timing circuit that allows the sharpener to stroke the cutting edges of the razor blades for a predetermined period of time, such as 20 to 60 seconds, preferably about 35 seconds, before automatically shutting off the motor.
The electrical and mechanical components of the carriage and its drive system, including all moving parts, are housed preferably within a thin plastic shell. None of the moving parts are visible to the eye, except for a partly visible portion of the abrasive slide, which may be seen through a blade-mounting slot located in a front wall of the housing when the razor head is absent from the slot. When the razor is mounted for sharpening, the rearward most portion (distal end) of the razor handle rests within a slidable cradle, which is spring biased so as to push the razor blade head into the blade-mounting slot so that each razor blade firmly rests against the abrasive slide which is located within the housing adjacent and opposite to the inner side of the blademounting slot. The tension of a spring mounted between a stud on the cradle and a stud on the housing causes the razor to remain firmly in the required position for sharpening the blade(s) during the sharpening cycle of the apparatus.
While the present device has a similar sharpening ability as the hand operated device previously mentioned, the present device achieves an improved degree of sharpness by means of the electrically operated arrangement that accomplishes automatically what was previously accomplished by a hand stroking action. Although the sharpening performance of the present motorized device may be comparable to the sharpening performance of the hand stroked device, one advantage of the present device is that it provides a simple and precise way to mount the razor blade to achieve the sharpening process with little or no manual effort and in the shortest possible time.
In the present disclosure, the razor blade head and its handle are mounted in a simple and precise way to allow the planar slide of the abrasive substance to move back and forth over the cutting edge of the blade(s) through a stroking distance of about 1 to about 1.5 inches, more preferably about 1.0625 inches. This oscillatory motion is provided by the cam assembly driven by the small electric motor. The oscillatory motion is preferably programmed to run for a predetermined period of time, such as 35 seconds, by the timing circuit.
The abrasive slide, which hones the edge of each razor blade, is designed to fit between the outer lips of the head that supports the razor blade(s). This provides the track effect that guides the blade(s) relative to the abrasive slide during the oscillatory sharpening motion of the latter. Testing of the present motorized sharpening device indicates that the useful life of typical hand-held razors, such as a GILLETTE, SCHICK and BIC, may be extended from about 10 to about 150 shaves, or about 1500%. Such improved sharpening performance could result in a substantial economic improvement to the user, while continuing to provide smooth and close shaves with minimal cuts or nicks.